I agree and am currently engaged in a prolonged in depth study of waymarks, trade routes and boundaries. Often particularly difficult for two reasons:
1 The Romans "improved" and developed earlier trackways and too much emphasis is placed upon routes as being virgin Roman inventions. Look beyond and before.
2 New age mumbo-jumbo and earth energy fantasy means that few serious writers look at prehistoric tracks and non astronomical alignments seriously.
The key is found by trying to understand the geography - not the cosmology or religion. Landscape is key. Look at the landforms, the valleys, the wet places, the heavily wooded ground, the fording places. These were the factors that determined communication and trade. That leads us on to understand why straight lines were sought and routes marked. Perfectly reasonable then to see barrows and ritual places associated with routes of passage as well as rites of passage.